A family of 9H-thioxanthen-9-one derivatives and two precursors, 2-[(4-bromophenyl)sulfanyl]-5-nitrobenzoic acid and 2-[(4-aminophenyl)sulfanyl]-5-nitrobenzoic acid, were synthesized and studied in order to assess the role of the different substituent groups in determining the supramolecular motifs. From our results we can conclude that Etter's rules are obeyed: whenever present the –COOH head to head strong hydrogen bonding dimer, R22(8) synthon, prevails as the dominant interaction. As for –NH2, the best donor when present also follows the expected hierarchy, an NH⋯O(COOH) was formed in the acid precursor (2) and an NH⋯O(CO) in the thioxanthone (4). The main role played by weaker hydrogen bonds such as CH⋯O, and other intermolecular interactions, π–π and Br⋯O, as well as the geometric restraints of packing patterns shows the energetic interplay governing crystal packing. A common feature is the relation between the π–π stacking and the unit cell dimensions. A new synthon notation, RR′, introduced in this paper, refers to the possibility of accounting for intra- and intermolecular interactions into recognizable and recurring aggregate patterns.
我们合成并研究了一系列 9H-
噻吨-9-酮衍
生物和两种前体,即 2-[(4-
溴苯基)
硫]-5-硝基
苯甲酸和 2-[(4-
氨基苯基)
硫]-5-硝基
苯甲酸,以评估不同取代基团在决定超分子结构方面的作用。根据研究结果,我们可以得出这样的结论:Etter 规则得到了遵守:只要存在 -COOH 头对头强氢键二聚体,
R22(8) 合子就会成为主要的相互作用。至于 -NH2,最佳供体的出现也遵循了预期的层次结构,在酸前体 (2) 中形成了 NH⋯O(COOH),在
硫杂
蒽酮 (4) 中形成了 NH⋯O(CO)。CH⋯O 等较弱的氢键、π-π 和 Br⋯O 等其他分子间相互作用以及堆积模式的几何约束所发挥的主要作用显示了晶体堆积的能量相互作用。一个共同的特征是 π-π 堆积与单位晶胞尺寸之间的关系。本文引入了一个新的合成符号 RR′,指的是将分子内和分子间的相互作用纳入可识别和重复出现的聚合模式的可能性。